I used to regret coming into this world mere months after the final Apollo mission, thinking I had missed the great age of exploration. But I no longer do. In just the last six months, I have seen the launch of the two most powerful rockets ever built, the Space Launch System and Starship. I have seen the naming of not one but two crews that will fly around the Moon, Artemis II and the dearMoon project. As NASA says, we are going.

Yet still more remarkably, during the last half-year, I have seen two dozen rockets land on a drone ship and fly again. We no longer treat this as remarkable, but we absolutely should. These now-routine Falcon 9 first stage landings at sea are a harbinger of the future. //

This is a far more wonderful and wild time in space than any that came before. There is incredible opportunity and peril. The future is unknowable but tantalizing.

So I no longer have any regrets about missing Apollo. I am thrilled to be alive at this very moment in human history. //

pokrface Senior Technology Editor

ARS STAFF

Re: the ubiquity of reusability — when I'm doing Saturn V tour shifts, one of the most common questions people ask is whether the giant Saturn V they're standing next to ever flew, and how NASA recovered it. I would guess that out of everyone who asks a question about the rocket, 50% of them ask that one in particular. When I tell them that no, the Saturn V was a one-and-done thing and most of it was destroyed during launch, most folks are genuinely flabbergasted.

SpaceX has gotten so good at reusable rocketry that it's almost unbelievable. It's similarly unbelievable how quickly the idea of rockets that return and land on their own has become nor just normalized, but the expected way things are supposed to work.

Like Berger says, that's one of the most amazing shifts in perspective I've ever seen in my entire life.

One of the most iconic launch sites in the world, Vandenberg Space Force Base’s Space Launch Complex 6 (SLC-6), will be leased by SpaceX. Confirmation came after Col. Rob Long, Space Launch Delta 30 (SLD 30) commander, signed a statement supporting SpaceX’s lease to launch Falcon 9 and Falcon Heavy missions from the launch site.

Sky's Africa correspondent, Yousra Elbagir, watched as evacuees arrived in Saudi Arabia from Sudan on HMS Taif.

In the crowd, she spotted her uncle, Mohsin, a Sudanese-American surgeon, who boarded a ship in Port Sudan to escape the fighting in Khartoum.

Thursday 27 April 2023 19:18, UK

NTP Client (Network Time Protocol) is the software client that allows your router to synchronize with an available time server. Your router's current time is listed in the upper right hand corner of the Web GUI when you log in to your router. Certain features such as "Access Restrictions" and the "Traffic by Month" graph will not function if the router hasn't synchronized with a time server. And if it has synchronized but the time has not been adjusted for your time zone, you may see unexpected behavior. You cannot set your time manually, and must do it via NTP. Don't be fooled by the time zone setting located at "Setup" > "Basic Setup" > "Time Settings". This setting alone is only to adjust the synchronized time from the server to match your local time.

As Brainslayer states "If NTP is disabled the time starts at zero which is 1 January 1970".

As mentioned, you cannot just manually set the time on your router and then forget about it. You can, however, set it to synchronize with a public time server using the NTP client and then forget about it. To configure the NTP client, log into the router and go to "Setup" > "Basic Setup" > "Time Settings". Now:

1) Select "Enable" next to NTP Client
2) Choose the appropriate Time Zone for your area
3) Set Summer Time (DST) as appropriate (See Time Zone settings below)
4) Enter the domain name or IP address of the time server you have selected (See Time Servers below)

Don't forget to Save and Apply settings.

How often does NTP synchronize? According to redhawk0, it is "checked at boot up...then after 120 seconds for a second time....that's it."
http://www.dd-wrt.com/phpBB2/viewtopic.php?p=419797#419797

Have the clocks just changed in your area but you find that DD-WRT is still an hour behind/ahead? Open a Telnet/SSH command prompt and run these three commands:

ntpclient pool.ntp.org
stopservice process_monitor
startservice process_monitor

Courtesy: http://www.dd-wrt.com/phpBB2/viewtopic.php?p=271968#271968

The "write hole" effect can happen if a power failure occurs during the write. It happens in all the array types, including but not limited to RAID5, RAID6, and RAID1. In this case it is impossible to determine which of data blocks or parity blocks have been written to the disks and which have not. In this situation the parity data does not match to the rest of the data in the stripe. Also, you cannot determine with confidence which data is incorrect - parity or one of the data blocks.
Write hole in RAID5

"Write hole" is widely recognized to affect a RAID5, and most of the discussions of the "write hole" effect refer to RAID5. It is important to know that other array types are affected as well.

If the user data is not written completely, usually a filesystem corrects the errors during the reboot by replaying the transaction log. If a file system does not support journaling, the errors will still be corrected during the next consistency check (CHKDSK or fsck).

If the parity (in RAID5) or the mirror copy (in RAID1) is not written correctly, it would be unnoticed until one of the array member disks fails. If the disk fails, you need to replace the failed disk and start RAID rebuild. In this case one of the blocks would be recovered incorrectly. If a RAID recovery is needed because of a controller failure, a mismatch of parity doesn't matter.

A mismatch of parity or mirrored data can be recovered without user intervention, if at some later point a full stripe is written on a RAID5, or the same data block is written again in a RAID1. In such a case the old (incorrect) parity is not used, but new (correct) parity data would be calculated and then written. Also, new parity data would be written if you force the resynchronization of the array (this option is available for many RAID controllers and NAS). //

How to avoid the "write hole"?

In order to completely avoid the write hole, you need to provide write atomicity. We call the operations which cannot be interrupted in the middle of the process "atomic". The "atomic" operation is either fully completed or is not done at all. If the atomic operation is interrupted because of external reasons (e.g. a power failure), it is guaranteed that a system stays either in original or in final state.

In a system which consists of several independent devices, natural atomicity doesn't exist. Variance of mechanical hard drives characteristics and data bus particularities don't allow to provide required synchronization. In these cases, transactions are typically used. Transaction is a group of operations for which atomicity is provided artificially. However, expensive overhead is required to provide transaction atomicity. Hence, transactions are not used in RAIDs.

One more option to avoid a write hole id to use a ZFS which is a hybrid of a filesystem and a RAID. ZFS uses "copy-on-write" to provide write atomicity. However, this technology requires a special type of RAID (RAID-Z) which cannot be reduced to a combination of common RAID types (RAID 0, RAID 1, or RAID 5).